Guard for circular saws



March 24, 1931. DRYSDALE 1,797,907 7 GUARD FOR CIRCULAR SAWS Filed Jan. 26 Q 1926 A .FIG.

Patented Mar. 24; 1931 oFF-rcis AROLD G. DRYSDALE, or assesses, "iisw was GUARD son cisterns saws Application filed January 26;, 192%.; Seria1-N6. 83,878.

This invention relates to circular saw guards of the kind and 'variety chiefly supported by the saw spindle, such as shown in United States Patent 'No. 1,464,924, granted August 14th, 1923, and inpa-rticular to anchoring means for such saw guards.-

The principal objects ofthis invention are .to anchor the guard in a fixedp'osition rela- ,f

tive to the worktable When the saw is ready for use, interfering in" no way with the proper function of the guard when the saw is in use; and to mount the anchor in such a manner that its relation to the guardis maintained ready to function, whatever maybe the adjustment of saw projection above the work table. Other objects of this. invention are: .to so design the anchoring means as to choring the guard.

avoid interference with dust remover hoods as are frequently applied to such'machines; and to anchor such guards in a'uniform-ma'nner for a wide variety of machines, thereby eliminating special and cost-ly'iristallations 1rd excessive parts and thus effecting economy of manufacture. I w

Further objects and advantages will hereinaft er appear thru a study of the following specifications and accompanying drawing, in which:-' 1

Fig; 1 isan elevation ofga, convenient mounting of a saw guard with asaw 'to-V gether with my intention as a mean of Fig. 2 is a part section on line A A of Fig. 1 in the direction of the arrows.

LikeChata'cters refer to like parts in'both i views.

- o In the drawing Fig. suit saw as boijnd' between collar atashing 4,- a;ia 'fiasnsr5 under pressure of not 6 against shoulders of spindle 1, all of which rotate as a unit when spindle 1 is rotated. Guard. firenibers 1 i and 1-2 with their hubs 9 and i7 rspee:

*iii'r'ly are mounted and operable iir the'us'ual manner, rimneIy-thmeInbers 1O and-12am connected together bya spring 1-3 smbiam I their hubs 9 and 7 which .a-rerotatably 11 .15 is clear that; whe the spindle is ro- 1 ten they to.

sist iriecsts-ty-ivi-aue of the friction betweenbu hing4 and hub 7 Fig; 2, unless an interference 14 is presented suflicient to overcome the aforesaid friction,

thereby rendering the guard members 7, 9,

1 0, 12 motionless butgallowing the saw 3, col- ].ar 2; bushing- 4 washer 5 and nut 6 to turn with spindle 1.

Ar1n-15 having a bore 1" rotativelyiem bracing hub 7 of guard member 12 and held movably also between hub 9 land washer 5,

Fig. 2, terminates in st-lateralprojection or pin 14 which engages a 1ug'11onguard member In Fig. lten'sion-spring 18 engaging arm '15 as shownat 19 tends to rotate arm I counter to direction of rotationof saw '3 but.

arm 15 is of proper length to contact with underside :of work table 20 at 21 thus keep- I ing said arm in a fixed position, and allowbut'he'ld steady my anchoring device as before set for th. It is now desired to el'evate or lower the work table 20. This may be done in the usual manner without him "defance, for as the tablennioves, so does the "end of arm15i with its pin list-incite with it,

maintaining,- therefore; its contact at 21 by a reldtive'ly small angular inovenint about shaft- 1 and-in turn changing the angular position of the 10 and '12- iiiai1it a.ii1'iI1g,v however; the same relation of Mg 11 or work entrance 22 to Work table 20'; Itis obvious that-i n making lug '11follow pin Mandpin 1 E follow Work table 20,"then 111g '11 must follow work; tale-1s 20.

' Whenitis desired iiiake a but; the work,

ted to the sw m the direction ofarpushes against 1ug2'3; thereby rotati #1 1 9?! 12 fl ln 1 'clb k se the prsmfe; of spring; 13 until lug 23 is brought down flush with the work table when the front edge of the work emerges from the saw. When the back-edge of the work finally passes lug 11 of guard member which was held with ever increasing pressure against the under side of the work by the backward rotation of member 12 which rotation has gradually stretched, and thereby increased the tension of spring 13, lug 11 leaves pin 14 at 27 and guard-member. 1O fol lows the work until its rear edge has cleared the saw. Then, after the work has also passed the pressed-down lug 23 of guardmember 12, the friction between;hub 7 and bushing 4 causes the rotating saw to carry the guards back to their former position in which lug 11 engages pin 14 of anchor 15. Arm 15 and pin 14, being held in contact 21 with work table by means of anchor-spring 18, remain undisturbed.

Assume now, in case of a mounting on a saw machine carrying two saws, one saw like 3 mounted at each end of spindle carrier arm equidistantly from center of shaft '24 known as a universal saw, it is desired to move the bottom saw which is not shown, but is mounted substantially as is saw-3 with guard members like 10 and 12 and anchoring device as above described, each having similar engagement points for spring 18 at 19 and 28 respectively to the top and the top saw. 3 to the bottom by means of the usual operation of revolving the common spindle carrier arm 25 about shaft 24 Fig. 1. This is accomplished by swinging carrier arm 25 about shaft'24, Fig. 1, in a counter clockwise direction during which operation. arm 15 slides along undersideofwork table 20, arm 15 assuming .a changing angularity with reference to both shaft 24 and work table'20,; sliding contact tained by anchor spring 18. Itis readily seen that when thetop saw 8. and its guard consisting of members 10 and 12, has passed beneath and wellclear of the work table 20 a point is reached at whichthe arm 15 no longer contacts with the work table 20 as at 21. In such position arm 15 is still. restrained from' continuous rotation about spindle 1 by spring 18 Fig. 1 (the same force which previously maintained contact 21) and later,

sliding contact underside of work table 20 and in this condition with the saw 3 still revolving, the contact 27 of lug 11 is maintained with pin 14 Fig. 1. The latter condition of contact 27 between lug 11 and pin 14 is no longer important but the explanation is culiar action. Thus, in a sawing machine of the type described aboveand known as a universal saw the resilient locking means forming the connection between the two anchors, the locking of the upper anchor against-the work-table simultaneously eifectsthe locking of the lower anchorby holding the latter in table when the saw is raised into cutting posiline with the pulling direction of the looking spring, so that if, in extreme positions of the spindle carrier arm, the lower saw should revolve, its guard will be prevented by its anchor from rotating with it.

A tension spring 18 is attached at 19 and 28 to arm 15 and one similar arm, both of these latter arms bearing similar relation to their respective mountings, as do 19151012 and 17 Spring 18 maintains contact at 21 when the device is in use and holds arms similar to 15in a condition of rest when the saw at the other end of the spindle carrier arm is in use, but it is immaterial what means is employed, so long as the action is substantially as herein described. The mounting of arm 15as shown is designed to serve most practical applications, but may be arranged in various other ways for each individual case; therefore It is understood that modifications of the" preferred-embodiment herein described may be made'without'departingfrom the spirit and scope of my invention as claimed. xI-Iawing thus described my invention, I claim: 7'

1. In combination with the spring-connected'guardanembers of a circular saw, an anchor for the said guards, having its hub mounted loosely on the saw arbor and being held in tension against the underside of the the amount of rotation of the guard -membersbetween arm'15 and work table 20 being mamally projecting pin for engagement with a lug on one of the guard-members; and means for holding the sald anchor-arm resihently against the under side of the worktion. 7 r i .3. In combination with the spring con- -nected guard members'of each saw of a cirmade for a clearer .understandmg. of the pecular saw machine having two saw arbors mounted at opposite ends of a rotatable arm, said guards turnably pivoted on the arbor of;- their respective; saws and having a tendency to rotate with said saws, an anchor for each of said saw guards having a hub member turnably'carried on the said saw arbors, each of said anchors beingresil-iently held from rotation by a spring and each anchor having a laterally projecting pin for engagement with a lug on one of the guard members at each end of said rotatable arm, said engagement limiting the amount of rotation of said guards when their respective anchor is not in engagement with the Work table.

In testimony whereof I aflix my signatuure.

HAROLD G. DRYSDALE 

